It is known that improvements in the electrical characteristics of multiple-phase stators can be obtained by dividing each coil of each phase into two or more coil portions which are separated by coil portions of the other phases. Such a winding pattern may be referred to as a split-coil pattern. For example, in winding a three phase, eight pole stator, portions of the eight coils forming the first phase are wound, followed by portions of the eight coils forming the second phase, followed in turn by the winding of portions of the eight coils of the third phase. A second portion of the eight coils of the first phase is then wound into respectively the same core slots as the portions of the same first phase coils portions wound at the outset, and so forth, until all of the coils are wound. If each coil is wound in two portions, a total of 48 coil portions are wound.
Flier-type winding machines have mechanisms for holding the core of a part to be wound and indexing the core as required to place the appropriate coil-receiving slots into a position to have coils wound therein by rotation of the flier. Typical stator coil winding patterns practically preclude the use of but one coil-winding flier. Accordingly, when winding a stator having 48 separately wound coil portions, the stator core will have to be indexed into the various positions required to completely wind the stator a total of 48 times, once for each coil portion to be wound.
In addition to winding coils, it is desirable during the winding process to mechanically connect the start and finish lead wire ends of each phase to terminals mounted on the stator core. The time taken to make the terminal connections appreciably adds to the total time required to fully wind the stator core and effect terminal connections.
Normal practice when winding multiple phase stators by a flier-type winding machine is to wind a first coil of the first phase, index the stator core in a predetermined direction about its axis to position the stator core relative to the flier to enable the winding of the second coil of the first phase, and repeating this process until all of the coils of the first phase are wound, each time indexing the stator core in the same predetermined direction. After another index, the coils of the second phase are wound, with the stator core indexed in the same forward direction after each coil but the last is wound. The direction of index of the stator core for the winding of the third phase is the same as for the winding of the coils of the second phase.
After the winding of all three phases is completed, the lead wires, i.e. both the start and finish wires, extending to and from each phase are typically connected by hand to terminals, which may be mounted on the stator core by means of a "terminal board." Six terminal connections are required, two for each phase. If the stator is wound with a split-coil winding, 12 terminal connections are required, two for each one-half phase wound.
Stators having outwardly-opening coil-receiving slots have been wound using a flier-type winding apparatus of a type more typically used for winding armatures. Typical flier-type winding machines employ a collet mechanism to grip the shaft of an unwound armature during the winding operations. For winding stators which do not have a shaft, a practice has been to affix a dummy shaft aligned with the bore of the stator and grip the dummy part by a collet associated with the stator winding machine. Such collet mechanisms are generally operated by use of a rod that extends within a rotator shaft, which rod is either extended or retracted to actuate the collet mechanism. Examples of such collet mechanisms, as used in armature winding machines, are illustrated in the aforementioned '313 and '856 patents and in U.S. Pat. Nos. 4,826,092 and 5,127,594.
In many instances of winding coils for a dynamoelectric device, such as a stator or armature, a single winding form configuration is sufficient for the winding of all of the coils. In such instances, the use of a conventional winding form assembly that has an integral lead guide mechanism having its lead guide-carrying components carried externally on one of the side plates is acceptable. However, in other instances, particularly in those cases in which the coil span subtends a shallow angle, such as in 4, 6 or 8 pole armatures or stators, it is desirable to use different winding forms having different wire-guiding characteristics for different sets of the coils to be wound. These different wire-guiding characteristic may be obtained, for example, by changing the side plates that form the winding form assembly. Removal and replacement of such side plates can be a complex task, and the costs of side plates quite high if, as often the case, the winding form is provided with movable lead guides that assist in guiding the lead wires extending to and from the wound coils around tangs or hooks on a commutator of an armature being wound or on a terminal board affixed to a stator core being wound.